In recent years, apparatuses that compress images by implementing an encoding method for compressing image information through orthogonal transform such as discrete cosine transform and motion compensation by using redundancy inherent to image information, have been spreading so as to handle image information as digital information and achieve high-efficiency information transmission and accumulation in doing do. This encoding method may be Moving Picture Experts Group (MPEG), H.264, MPEG-4 Part 10 (Advanced Video Coding, which will be hereinafter referred to as AVC), or the like.
At present, to achieve higher encoding efficiency than that of H.264/AVC, a coding method called High Efficiency Video Coding (HEVC) is being developed as a standard by JCTVC (Joint Collaboration Team-Video Coding), which is a joint standards organization of ITU-T and ISO/IEC.
Also, in HEVC, range extensions (HEVC Range Extensions) are being considered so as to support high-end formats, such as images in chrominance signal formats like 4:2:2 and 4:4:4, and profiles for screen content (see Non-Patent Document 1, for example).
Meanwhile, IntraBlockCopy (IntraBC) is an encoding tool for performing motion compensation in a screen. IntraBC is known as a tool that contributes to improvement of efficiency in encoding an artificial image, such as a computer screen or a CG image.
However, IntraBC is not used as a technology for the above described HEVC Range Extensions, and is being considered as a standardized technology for screen content coding (SCC) extensions.